Three-phase reactor comprising iron-core units and coils

This application is a divisional of U.S. application Ser. No. 16/864,952, filed May 1, 2020, which is a divisional of U.S. application Ser. No. 15/400,066, filed Jan. 6, 2017, which claims priority to Japanese Application No. 2016-160747, filed Aug. 18, 2016, and Japanese Application No. 2016-014484, filed Jan. 28, 2016, the teachings of which are herein incorporated by reference.

The present invention relates to a three-phase reactor including iron-core units and coils.

Ordinarily, three-phase reactors include three iron cores and three coils wound around the iron cores. Japanese Unexamined Patent Publication (Kokai) No. 2-203507 discloses a three-phase reactor including three coils placed side by side. International Publication No. WO 2014/033830 discloses that the corresponding central axes of plural coils are arranged around the central axis of a three-phase reactor. Japanese Unexamined Patent Publication (Kokai) No. 2008-177500 discloses a three-phase reactor including plural straight magnetic cores that are radially arranged, connecting magnetic cores that connect the straight magnetic cores, and coils that are wound around the straight magnetic cores and the connecting magnetic cores.

A three-phase alternating current passes through a coil in each phase of a three-phase reactor. In the three-phase reactor that is conventional (Japanese Unexamined Patent Publication (Kokai) No. 2-203507), the length of a magnetic path through which magnetism generated when currents pass through coils in two optional phases passes may depend on the combination of the phases. Accordingly, there has been a problem that even when three-phase alternating currents in equilibrium are passed through the corresponding phases of a three-phase reactor, the densities of magnetic fluxes passing through iron cores in the corresponding phases are different from each other, and inductances are also imbalanced.

In the three-phase reactor that is conventional (Japanese Unexamined Patent Publication (Kokai) No. 2-203507), it may be impossible to symmetrically arrange iron-core coils in corresponding phases. Therefore, magnetic fluxes generated from the iron-core coils cause imbalanced inductances. When inductances are imbalanced in a three-phase reactor as described above, it is impossible to ideally output a three-phase alternating current even if the three-phase alternating current is ideally inputted.

In the three-phase reactors that are conventional (Japanese Unexamined Patent Publication (Kokai) No. 2-203507 and International Publication No. WO 2014/033830), the dimensions of gaps (thicknesses of gaps) depend on the dimensions of a commercially available gap member. Therefore, the winding number and cross-sectional area of a coil may be limited by the dimension of a gap member when the structure of a three-phase reactor is determined. The precision of inductances in a three-phase reactor depends on the precision of the thickness of a gap member. Because the precision of the thickness of a gap member is commonly around ±10%, the precision of inductances in a three-phase reactor also depends thereon. It is also possible to produce a gap member having a desired dimension while the cost of the gap member is increased.

In order to assemble a three-phase reactor, a step of assembling the core members of the three-phase reactor on a one-by-one basis, and a step of connecting some core members to each other are preferably performed several times. Therefore, there is a problem that it is difficult to control the dimension of a gap. In addition, a manufacturing cost is increased by improving the precision of the thickness of a gap member.

A core member is ordinarily formed by layering plural steel sheets for layering. A three-phase reactor preferably has a portion in which core members come in contact with each other. In addition, it is preferable to alternately layer the steel sheets for layering in order to enhance the precision of the contact portion. Such operations have been very complicated.

Further, the three-phase reactors that are conventional (Japanese Unexamined Patent Publication (Kokai) No. 2-203507 and International Publication No. WO 2014/033830) have a problem that a magnetic field leaks out to an air area around a coil in such a three-phase reactor because the coil is exposed to the outside. The magnetic field that has leaked out can influence a heart pacemaker, and can heat a magnetic substance around such a three-phase reactor. In recent years, amplifiers, motors, and the like have tended to be driven by higher-frequency switching. Therefore, the frequency of high-frequency noise can also become higher. Thus, it is also conceivable that the influence of the magnetic field that has leaked out on the outside becomes greater.

Further, the three-phase reactors that are conventional (Japanese Unexamined Patent Publication (Kokai) No. 2-203507 and International Publication No. WO 2014/033830) have a problem that a magnetic flux that has leaked out of a gap causes an eddy-current loss in a coil, thereby increasing the loss of the coil, because the coil is arranged close to the gap. A method of making a structure in which the coil is located away from the gap can be provided in order to solve the problem. However, the method has a demerit that a weight and a cost are increased because the core and the winding diameter of the coil become large.

The problem that the inductances are imbalanced can be solved by enlarging only the gap of a central phase. However, a magnetic field is allowed to further leak out by enlarging the gap.

Further, in the reactors having the conventional structures (Japanese Unexamined Patent Publication (Kokai) No. 2-203507 and International Publication No. WO 2014/033830), the temperatures of a coil and a core have tended to easily become unbalanced because of high thermal resistance between the coil and the core. In order to eliminate the unbalance between the temperatures, the entire coil may be molded with resin to bring the coil into intimate contact with the core. However, there is a problem that a cost is increased. Further, in order to suppress noise generated from a gap, design can be performed such that a magnetic flux density is reduced, and molding with resin can be performed as described above. However, there is also a problem that a cost is increased.

Methods for solving the above-described problems of the imbalance in inductances, the leakage of a magnetic field due to a coil exposed to the outside, and a gap dimension also include such a technique as described in Japanese Unexamined Patent Publication (Kokai) No. 2008-177500. It is described that inductances can be offered by supplying a current to a control winding without disposing a gap in the technique. However, the technique has a problem that a control circuit for controlling a current passed through the control winding is demanded, whereby an unnecessary power is consumed by the control winding. Further, the technique also has a problem that a magnetic field generated from the control winding leaks out to an area around the control winding because the control winding is exposed to the outside.

The present invention was accomplished under such circumstances with an object to provide a three-phase reactor with gaps, which inhibits inductances from being imbalanced and a magnetic field from leaking out to the outside, and in which a control winding is unnecessary, and a loss caused by a leakage flux can be reduced.

In order to achieve the object described above, according to a first aspect of the present invention, there is provided a three-phase reactor including: an outer peripheral iron core; and at least three iron-core coils that come in contact with an inner surface of the outer peripheral iron core or are joined to the inner surface, wherein the at least three iron-core coils include corresponding iron cores and corresponding coils wound around the iron cores; and gaps that can magnetically connect one iron-core coil of the at least three iron-core coils and an iron-core coil adjacent to the one iron-core coil to each other are formed between the one iron-core coil of the at least three iron-core coils and the iron-core coil adjacent to the one iron-core coil.

According to a second aspect of the present invention, the number of the at least three iron-core coils is a multiple of 3 in the first aspect of the present invention.

According to a third aspect of the present invention, the iron cores of the at least three iron-core coils include plural iron-core units; and iron-core unit gaps that can magnetically connect the plural iron-core units are formed between the plural iron-core units in either the first or second aspect of the present invention.

According to a fourth aspect of the present invention, outer peripheral iron-core gaps that can magnetically connect the iron cores of the at least three iron-core coils and the outer peripheral iron core to each other are formed between the iron cores of the at least three iron-core coils and the outer peripheral iron core in any of the first to third aspects of the present invention.

According to a fifth aspect of the present invention, the outer peripheral iron core includes plural outer peripheral iron-core units in any of the first to fourth aspects of the present invention.

According to a sixth aspect of the present invention, outer peripheral iron-core unit gaps are formed between outer peripheral iron-core units, adjacent to each other, of the plural outer peripheral iron-core units in the fifth aspect of the present invention.

According to a seventh aspect of the present invention, the at least three iron-core coils are rotationally symmetrically arranged in any of the first to sixth aspects of the present invention.

According to an eighth aspect of the present invention, the three-phase reactor includes: a first set including at least three iron-core coils; and a second set including at least three other iron-core coils in any of the first to seventh aspects of the present invention.

According to a ninth aspect of the present invention, the three-phase reactor includes not less than three sets, each of which includes three iron-core coils in the eighth aspect of the present invention.

According to a tenth aspect of the present invention, a gap member, insulating paper, or resin which is a non-magnetic material is inserted or filled into the gaps of the three-phase reactor in any of the first to ninth aspects of the present invention.

According to an eleventh aspect of the present invention, a gap member, insulating material, or resin which is a non-magnetic material is filled into an inside of the outer peripheral iron core of the three-phase reactor in any of the first to ninth aspects of the present invention.

According to a twelfth aspect of the present invention, there is provided a three-phase reactor including: an outer peripheral iron core; and at least three iron-core coils that come in contact with an inner surface of the outer peripheral iron core or are joined to the inner surface, wherein the at least three iron-core coils include corresponding iron cores and corresponding coils wound around the iron cores; the three-phase reactor further includes inter-coil iron cores arranged between the at least three iron-core coils; and gaps that can magnetically connect the at least three iron-core coils and the inter-coil iron cores to each other are formed between the at least three iron-core coils and the inter-coil iron cores.

According to a thirteenth aspect of the present invention, each of the inter-coil iron cores includes two surfaces making an acute angle with each other; and the two surfaces face the corresponding iron-core coils across the corresponding gaps in the twelfth aspect of the present invention.

According to a fourteenth aspect of the present invention, the number of the at least three iron-core coils is a multiple of 3 in either the twelfth or thirteenth aspect of the present invention.

According to the fifteenth aspect of the present invention, the iron cores of the at least three iron-core coils include plural iron-core units; and iron-core unit gaps that can magnetically connect the plural iron-core units are formed between the plural iron-core units in any of the twelfth to fourteenth aspects of the present invention.

According to a sixteenth aspect of the present invention, outer peripheral iron-core gaps that can magnetically connect the iron cores of the at least three iron-core coils and the outer peripheral iron core are formed between the iron cores of the at least three iron-core coils and the outer peripheral iron core in any of the twelfth to fifteenth aspects of the present invention.

According to a seventeenth aspect of the present invention, the inter-coil iron cores include plural inter-coil iron-core units; and inter-coil iron-core unit gaps that can magnetically connect the plural inter-coil iron-core units are formed between the plural inter-coil iron-core units in any of the twelfth to sixteenth aspects of the present invention.

According to an eighteenth aspect of the present invention, the outer peripheral iron core includes plural outer peripheral iron-core units in any of the twelfth to seventeenth aspects of the present invention.

According to a nineteenth aspect of the present invention, outer peripheral iron-core unit gaps are formed between outer peripheral iron-core units, adjacent to each other, of the plural outer peripheral iron-core units, in the eighteenth aspect of the present invention.

According to a twentieth aspect of the present invention, the three iron-core coils are rotationally symmetrically arranged in any of the twelfth to nineteenth aspects of the present invention.

According to a twenty-first aspect of the present invention, the three-phase reactor includes: a first set including three iron-core coils; and a second set including three other iron-core coils in any of the twelfth to twentieth aspects of the present invention.

According to a twenty-second aspect of the present invention, the three-phase reactor includes not less than three sets, each of which includes three iron-core coils in the twenty-first aspect of the present invention.

According to a twenty-third aspect of the present invention, a gap member, insulating paper, or resin which is a non-magnetic material is inserted or filled into the gaps of the three-phase reactor in any of the twelfth to twenty-second aspects of the present invention.

According to a twenty-fourth aspect of the present invention, a gap member, insulating material, or resin which is a non-magnetic material is filled into an inside of the outer peripheral iron core of the three-phase reactor in any of the twelfth to twenty-second aspects of the present invention.

According to a twenty-fifth aspect of the present invention, there is provided a motor driving device including the reactor according to any of the first to twenty-fourth aspects of the present invention.

According to a twenty-sixth aspect of the present invention, there is provided a machine including the motor driving device according to the twenty-fifth aspect of the present invention.

According to a twenty-seventh aspect of the present invention, there is provided a power conditioner including the reactor according to any of the first to twenty-fourth aspects of the present invention.

According to a twenty-eighth aspect of the present invention, there is provided a machine or device including the power conditioner according to the twenty-seventh aspect of the present invention.

The objects, features, and advantages as well as other objects, features, and advantages of the present invention will become clear due to detailed descriptions of exemplary embodiments of the present invention illustrated in the accompanying drawings.

Embodiments of the present invention will be described below with reference to the accompanying drawings. In the following drawings, similar members are denoted by similar reference characters. The reduction scales of the drawings are varied as appropriate in order to facilitate understanding.

is a top face view of a three-phase reactor according to a first embodiment of the present invention. Further,is a cross-sectional view of the three-phase reactor illustrated in, andis a perspective view of the three-phase reactor illustrated in.

As illustrated in,, and, a three-phase reactorincludes: an outer peripheral iron core; and three iron-core coilstoof which each is magnetically connected to the outer peripheral iron core. In, the iron-core coilstoare arranged in the inside of the outer peripheral iron corehaving a ring shape. The iron-core coilstoare spaced from each other circumferentially at regular intervals in the three-phase reactor.

As can be seen from the drawings, the iron-core coilstoinclude: corresponding iron corestothat radially extend; and corresponding coilstowound around the iron cores. The radially outer end of each of the iron corestocomes in contact with the outer peripheral iron core, or is formed integrally with the outer peripheral iron core.

Further, the radially inner end of each of the iron corestois located in the vicinity of the center of the outer peripheral iron core. Inand the like, the radially inner end of each of the iron corestoconverges toward the center of the outer peripheral iron core, and the front end angle of the radially inner end is about 120 degrees. The radially inner ends of the iron corestoare spaced from each other through gapstothat can magnetically connect the radially inner ends to each other.

In other words, in the first embodiment, the radially inner end of the iron coreis spaced from each of the radially inner ends of the two adjacent iron cores,through each of the gaps,. The same also applies to the other iron cores,. The dimensions of the gapstoare intended to be equal to each other. In embodiments described later, illustrations of the gapstomay be omitted.

The three-phase reactorcan be formed to be lightweight and simple because a central iron core located in the center of the three-phase reactoris unnecessary in the present invention as described above. Further, the three iron-core coilstoare surrounded by the outer peripheral iron core, and therefore, a magnetic field generated from the coilstodoes not leak out to the outside of the outer peripheral iron core. Further, the gapstohaving optional thicknesses can be inexpensively disposed, and therefore, the reactor is more advantageous in view of design than reactors having conventional structures.